Controlled oxidation of Ni for stress-free hole transport layer of large-scale perovskite solar cells
Controlled oxidation of Ni for stress-free hole transport layer of large-scale perovskite solar cells
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DOI：
10.1007/s12274-019-2556-8
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发表时间：
2019-11
期刊：
影响因子：
9.9
通讯作者：
Seongha Lee;H. Roh;G. Han;Jung‐Kun Lee
中科院分区：
文献类型：
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作者：
Seongha Lee;H. Roh;G. Han;Jung‐Kun Lee
研究了NiO薄膜的残余热应力对倒置型钙钛矿太阳电池性能的影响。在这项研究中，NiO薄膜生长在不同的表面粗糙度的氟掺杂的氧化锡（FTO）基板上的热氧化镍膜，并进行了测试，作为大规模的钙钛矿太阳能电池的空穴传输层。实验和模拟结果表明，抑制Ni膜氧化过程中NiO-FTO界面残余应力的出现对于有效的空穴提取是非常重要的。在平坦的FTO膜上的Ni氧化由于Ni膜体积膨胀而在NiO膜中产生面内压应力。这导致形成包括小气泡的缺陷。这些残余应力和缺陷增加了通过NiO膜的漏电流，防止空穴在NiO-钙钛矿界面处被选择性地收集。然而，当在粗糙表面上沉积和氧化Ni时，NiO膜的残余应力可以忽略不计，并且保持其固有的高电阻。无应力NiO膜是一种优异的空穴传输层，其阻止钙钛矿层的光生电子移动到FTO。通过设计残余应力来改善NiO膜的结构和电学质量，减少了载流子复合，并将钙钛矿太阳能电池的功率转换效率提高到16.37%。
The effect of the residual thermal stress of NiO films on the performance of an inverted type perovskite solar cell was studied. In this study, NiO films were grown on fluorine doped tin oxide (FTO) substrates of different surface roughness by thermally oxidizing Ni film and were tested as a hole transport layer for large-scale perovskite solar cells. Experimental and simulation results show that it is very important to suppress the appearance of the residual stress at the NiO-FTO interface during the oxidation of the Ni film for effective hole extraction. The Ni oxidation on the flat FTO film produced in-plane compressive stress in the NiO film due to the Ni film volume expansion. This led to the formation of defects including small blisters. These residual stress and defects increased leakage current through the NiO film, preventing holes from being selectively collected at the NiO-perovskite interface. However, when Ni was deposited and oxidized on the rough surface, the residual stress of the NiO film was negligible and its inherent high resistance was maintained. Stress-free NiO film is an excellent hole transport layer that stops the photogenerated electrons of the perovskite layer from moving to FTO. The improvements in the structural and electrical qualities of the NiO film by engineering the residual stress reduce the carrier recombination and increase the power conversion efficiency of the perovskite solar cells to 16.37%.